Electric heater



Feb. 24, 1931.

1 RElcHoLD 1,794,120

ELECTRIC HEATER Filed sept. 4, -1926 y l I gjf:

Patented Feb. 24, 1931 UNITED STATES PATENT OFFICE LUGWIG REICHOLD, OF WINSTED, CONNECTICUT, ASSIGN OR T0 THE FITZGERALD MFG. COMPANY, OF TORRINGTON, CONNECTICUT, A CORPORATION OF CONNECTICUT ELECTRIC HEATER Application filed September 4, 1926.

This invention relates to improvements in electric heaters, which are removable from the utensils in which employed for easy replacement in ease of damage.

According to this invention, the removable heater assembly includes a support for the conductor wires and resistive element proper, as well as the necessary quick-detachable couplings whereby all electrical elements and connections may be readily removed from the utensil for inspection and possible repair without breaking or altering the electrical connections or elements inter se. This support includes portions which aline and sustain the heater, when in position within the utensil, out of electrical contact between the resistive element proper and adjacent and cooperating parts of the utensil. Then removed, the resistive element proper is exposed to immediate inspection for its entire length, and may be readily repaired. Further, since all electrical parts are withdrawn when the device is removed from the utensil, a spare assembly may be immediately substituted and work resumed, all without any disruption of the electrical connections of the assembly.

In prior devices, it has been proposed to provide removable resistive elements for such apparatus; but in practically all cases, terminal members were provided which must be released before the element proper could be removed or even conveniently inspected. It was further necessary to provide insulating materials upon the utensil to prevent electrical contact between the resistive ,element proper and the walls of the utensil whereby the conduction and radiation of heat was hindered. The resistive element could not be readily tested with standard plug coniiections, after withdrawal, since its terminals in such were disconnected prior to its being dismounted.

On the accompanying drawings, in which an illustrative form of the invention is set forth- Figure- 1 is a side elevation of the heater assembly, with partial sections;

Fig. 2 is a top plan of the terminal block;

Serial No. 133,610.

general electric arrangement of the assems The resistive element proper 10 is, for example, of nichrome wire, wound to form a helical coil` which is then itself wound into a helix and supported in the helical groove ot an insulating base member 11. At thel free end. or that away from the terminal connections. a disk ot' insulating material 12 is provided concentrically with the axis of the member 11; this disk ispreferably of mica, which enables the assembly to withstand a high degree of heat. In order to protect the edges of this mica disk 12, it is preferred to provide a shoe 13 about it, which may be a thin annular piece of metal spun over the edge, as shown. At the other or terminal end, a similar disk la is provided with a shoe 13. In order to hold these disks and other members in place, a core bolt 15 is passed through an axial chamber of the member 11, and nuts 16 thereon hold the several parts rigidly together. These disks and shoes are rigid with regard to the bolt 15 and the heater element 10, and support them out of Contact with the metal wall lV of the utensil.

The terminal block consists of the basev plate 17 of sheet metal which is appropriately formed by punching and stamping operations to have the laterally out-bent feet 18 for guiding and support-ing the heater, as set forth in my co-pending application Serial No, 133,611, filed Sept. 1l, 1926, which has is sued as Patent 1,673,708, June 12, 1928, to which reference is made for one method of employing such an assembly. Between these feet, the edges of the base plate are curled downwardly to form a cup, which receives and guides the insulating sheet 19 of mica. The terminal 'prongs 20 are of the usual form, and have the enlarged portions 21 adjacent the lower end, and 'are screw-threaded for the stubs 2O:1L which project through apertures in the :base plate 17. Both of these prongs Z V i ings 22 and insulating washers 23. Olne of the terminal stubs 2Oa likewise receives a supporting bracket member 24 of sheet metal which is clamped thereto in electrical contact by the nut 26, and is re-bent into a plane substantially at right angles tothe axis of the core bolt 15, and is received thereover and clamped ther-ete in electrical contact and in rigid mechanical relation by the nuts 27. The position of the feet 18 along the core bolt may be adjusted by an appropriate movement of these nuts 27; and the separation of these feet from the axis of the boltA 15 by the radial movement of the bracket 24, as permitted by the slot 242L therein (Fig. 4).

One end of the resistive element 10 passes through the insulating bushing 12 and is engaged in electrical contact with the adjacent end of the core bolt 15 by the nut 28 and clamping device 28% The other end of the element 10 passes through the insulating bushing 14 and is held in electrical contact with the .stub of the remaining prong 2O by the nut 29 and clamping device 29a. The electrical circuit, therefore, is from one prong 2O and its stub 20a, through the bracket 24 to the core bolt; along the core bolt to the free end of the assembly, thence returning through the resistive element 10 to the other stub 20a and the other terminal prong 20.

It will be noted that all parts are held rigidly in mechanical relation to each other whether assembled in the utensil, or removed therefrom for inspection. In case of repair, the nuts 28 and 29 are released and the damaged heater coil 10 removed and a new one inserted: all of which is accomplished without aifecting the rigidity of the assembly'support. The double mechanical and electrical functions of the parts permit a cheap, simple and rigid assemblage.

It is obvious that the invention is not limited to the illustrative form presented, but that it may be applied in many ways within the scope of the appended claims.

Having thus described the invention, wh at I claim as new and desire to secure by Letters Patent, is-

1. In an electrical heater, a core bolt, an insulating sleeve on said bolt, a helical resistive heater element helically wound upon said sleeve, spacing and insulating washers on said bolt at the ends of said sleeve, a metallic bracket supported by and in electrical connection with on-e end of said bolt, a base plate insulated from said bracket and bolt and having guide feetV thereon, terminal prongs supported on, but insulated from said base plate, one of said prongs being in electrical and mechanical supporting relation with said bracket, an electrical connection between one end of said element and said other prong, and an electrical connection between he other end of said heater element and said o t. l

2. In an electric heater, asupport, a resistive heating element on said support, a base plate, a terminal prong having a stub passing through said base plate, means to insulate said prong and stub from said base plate, a bracket rigidly mounted on said support, and means for rigidly and electrically connecting said bracket and said stub, whereby said base late is supported rigidly with regard to, but insulated from said bracket.

3. In an electric heater, a supporting bolt, an insulating sleeve around said bolt, insulating disks at the ends of said sleeve and around said bolt, means to clamp said disks and sleeve into fixed relation to said bolt, a resistive heating element on said sleeve, a terminal at one end of said bolt mechanically supported thereby and electrically connected thereto, a base plate supported on and insulated from said terminal, a second terminal supported on an-d insulated from said base plate, said disks supporting the bolt and element in spaced relation from a support for the same, a connection from said element passing through one of .said disks to said second terminal.v and a connection from the other end of said element passing through another of said disks and connected to said bolt.` said bolt forming a return conductor to said other terminal.

In testimony whereof, I affix my signature.

LUDIVIG REICI-IOLD. 

